Known is a machine for flash-butt welding of rails (see USSR Auth. Cert. #129758), which incorporates a welding transformer, contact clamping jaws, clamping mechanism with a hydraulic drive and upsetting hydraulic drive fitted with the device for implementing the assigned program of changing the speed of displacement and upsetting of the rails being welded, in which the machine case is made in the form of two tong-type clamps carried by a common axle, and put onto the rails being welded, from the top in the suspended condition.
Known is a flash-butt welding machine (see USSR Auth. Cert. #201561) incorporating two tongue-like clamping devices for mounting and fastening the items being welded, welding transformers with current-carrying clamping jaws and hydraulic drives for clamping and displacement of items in flashing and upsetting, in which the clamping devices are connected to each other by three rods, two of which are located symmetrically relative to the item in one plane with it, and the third central rod which is the axis of rotation of the levers of one of the tong-type clamping devices, passes inside the sleeve which is the axis of rotation of the levers of the second clamping device, the central rod with the sleeve being the guide for relative displacement of the clamping devices.
Known is a device for flash removal from the rails after flash-butt welding, mounted separately from the welding machine and removing the flash in the cold state, which takes a great effort and long time. U.S. Pat. No. 3,336,839 cl.90-24, 1967.
It incorporates the foundation plate, side walls and the cover to which the frame guides are attached. The guide shafts are turned into the side walls. The cutters which remove the flash around the entire rails perimeter, are attached by screws to the mobile elements driven by the hydraulic or pneumatic cylinders through cranks, toothed racks or segments. Such a design of the device allows adjustment of the cutters position, depending on the rails type. The cutter removing the flash from the rails foot, is stationary fixed and does not touch the base metal of the rails.
Known is the device for flash removal from the rails, which is mounted on the tong-type rail welding machines, which consists of the case and three cutters which enclose the rail profile around its entire perimeter, and cut off the flash using the force of the welding machine upsetting cylinders. Here, the upper cutter is made of two parts, rigidly fixed on the case, while two symmetrical side cutters are mounted with the ability of rotation relative to the machine clamping levers, here the upper parts of the side cutters are joined to each other by a hinged tie rod. (USSR Author's Cert. #517429, cl.V23K Nov. 04, 1974 ).
The closest in technical essence, is the machine, described in the book "Equipment for flash-butt welding of rails and its operation", Naukova Dumka Publ. House, Kiev, 1974, p.73-84.
This machine with tong-type clamping, is designed for welding rails under the field conditions and incorporates two tong-type clamping devices carried by the common central axle, and insulated from each other, which are displaced relative to each other by two flashing-upsetting hydraulic cylinders connecting them and mounted in the centre of the cross-section of the rails being welded, with the bimetal current-carrying rods, two welding transformers connected by current-carrying jumpers through the current-carrying part of the rods of the flashing-upsetting hydraulic cylinders, with clamping current-carrying parts of the jaws made in the form of monolithic steel bars with copper deposits in the places of current supply.
Spring-loaded balls are mounted into the clamping jaws, for pressing up the rail with its rolling plane, to the rests mounted on the edges of the tong-type clamps. On the whole, the following drawbacks are found in all the machines for flash-butt welding of rails with tong-type clamping, including the above prototype:
1. Limited forces of upsetting and clamping which allow welding of relatively short rail sections, and do not permit welding of long sections, or welding with pressing up of the rails connected to the ties in track repair with a limitation on time, or welding of the closing butt when laying a seamless track.
2. Poor performance and low reliability are provided by the design in which the bimetal rods of the flashing-upsetting hydraulic cylinders are fastened to the wall of the lever of the stationary tong-type clamp by a ringlike protrusion on the current-carrying part of the rod, and captive ring which draws the rod by the protrusion to the lever wall by bolts, this weakening the wall, providing poor protection for the rod of the flashing-upsetting cylinders from the molten metal spatter, taking up a lot of space in the welding zone. Many machine components have to be disassembled, in order to remove the flashing-upsetting cylinder from the machine.
3. The spring-loaded balls mounted into the clamping jaws, do not ensure a reliable pressing of the rail with its rolling plane, to the rests of the tong-type clamps, which does not provide a good alignment of the rails.
4. Operation of the above devices requires holding for a certain time for strengthening of the welded butt; and than regripping of the clamps with opening of one of the machine clamps, which requires additional time during which the flash cools down, and its removal requires application of a considerable force and high power consumption, thus eliminating the possibility of welding the initially drawn up long rail sections and the closing butt, when laying a seamless track. The quality of flash removal deteriorates, because of the absence of the flash-remover cutters self-positioning.
The basic aim of the invention is development of a machine for flash-butt welding of rails in which: due to adding a new element into the design of the clamping hydraulic cylinder rod, design features of this new element, and new design of the flashing-upsetting hydraulic cylinders (tandem-cylinders), the relatively low pressure of the liquid coming to the clamping cylinder, changes to a higher pressure, without the application of any external supply lines, and, thereby the clamping force becomes greater, and the upsetting force also becomes greater with the application of tandem-cylinder, without increasing the diameters of the flashing-upsetting hydraulic cylinders or the pressure in them, this allowing long sections to be welded, welding with drawing up of the rails fastened to the ties in track repair, and welding of the closing butt when laying a seamless track to be performed, thus widening the functional capabilities of the machine; addition of the flash remover to the machine and the features of this device design, make possible the self-positioning of the cutters by the rail profile, flash removal in the hot condition from the rails clamped in the machine jaws, right after welding, with a smaller force, thus permitting the welding cycle time to be reduced, i.e. the productivity to be increased and the power consumption for flash removal to be decreased.